The invention relates to a flat link band of wire coils fabricated from an elastic material, for example the elastic material being plastic such as polyester or polyamide. The turn of each wire coil includes a head part and a foot part, identical or substantially identical to one another, formed in each case as a reverse loop. On the one hand, each head and foot extends over with a first shank section in a straight line or substantially in a straight line into corresponding first shank sections of, in each case the connecting turn. On the other hand, each head and foot part is connected over a second straight or substantially straight second shank section. In this arrangement, adjacent wire coils are adapted to be detachably held together with insert wires thrust into the interengaging head and foot part reverse loops.
Similar types of link bands are known in the prior art. For example, in one of these prior art types, the link bands are used, for example, as conveyor belts, sieve bands or the like. In this known link band, a plastic wire is first produced in advance to form a wire coil, preferably oval in cross section with no spacing between the adjacent coils, and is then joined with a coil of another link band that is similar but is provided with a reverse direction of rotation. In such a manner, when the wire coils are thrust into one another, they reciprocally adjust to one another by means of their diameters to provide corresponding larger spacings between the adjacent coils of each link band. Because of the recoil force of the wire coils positioned in such an engagement, there is provided a closed linkage therebetween.
The joining of these known link bands presents considerable difficulties, because the individual turns of the wire coils first have to be pushed or drawn to the right spacing therebetween, and then thrust into one another in the correct degree before the insert wire can be introduced therein. In the joined state of the wire coils, there arise tension states in the flat link band, inter alia because the wire coils have different directions of rotation. Furthermore, the wire coils of these known link bands have a tendency to curl counter to their direction of rotation, i.e., to loosen their stability in their joined state.
If the thermofixing, that is required with the known link band, is not carried out with an exact heat control, and the wire coils do not have extremely uniform dimensions, then no faultlessly flat surface structure can be produced. It has been proved already, solely by reason of the thickness tolerances of the plastic wires caused by the manufacturing technology and the fluctuations in the molecular structure, even with the most accurate possible application of heat during the wire coil production, that tensions in the link band cannot be avoided. In order nevertheless to achieve a certain standard, there is additionally required a thermofixing process, whereby the thermofixing temperature of the link band must be above the temperature of the intended later use thereof, in order to avoid any further problem with the tension differences therebetween. A further disadvantage of the known link band lies in its dependence upon the thickness of the wire used, because of which the permeability of the sieve band must find a lower limit.